Telomeres are the buffer DNA sequences at the end of chromosomes, which are there to protect the functional sections from being lost during cell replication. They get slowly eaten away as you age — and eventually the useful bits of the DNA start to get chopped off, too. However, unlike most types of cells, the telomere length in sperm actually lengthens as men get older — and that increased length is passed on to their children.

As Lamarckian as that may sound, this effect not only occurs, but is cumulative from generation to generation. In a study of 1,700 people from the Philippines, the longer fathers delayed having children, the longer the telomeres in their offspring... and the effect was cumulative going back at least one generation to the paternal grandfather, too.

In fact, each year the father delayed having children seemed to confer a benefit of one year of telomere length. The child of a 35-year old father would have 10 years more of telomere length to burn through than the child of a 25-year old.

The precise effect of telomere length is up for debate, it's certainly associated with the signs of biological aging, but both longer and shorter telomere lengths have been linked to various cancers at various times. If nothing else, the telomere length should mean your kids last just a bit longer on this planet — hopefully long enough to confer further benefits on their own spawn.